In the case of web-fed printing presses, the printing material is printed as web in the printing press and is additionally processed in many corresponding variations. The printing material is fed to the web-fed printing press in that the web-shaped printing material is unwound from a roll of the printing material. For this purpose, the roll is clamped into a device, in which the roll is unwound and the unwound printing material web is fed to the downstream parts of the web-fed printing press. Unwinders, dispensers, roll stands or reel splicers in different constructions are known from the prior art as devices for receiving a printing material roll, wherein the technical definitions or the technical differences, respectively, between the different names are fluid and can vary. Only the term reel splicer will be used below for all of these different concepts of unwinders, dispensers, roll stands or reel splicers.
The method according to the invention also applies to other processing processes and processing machines, in the case of which a web-shaped fluid-repellent material is processed in a different manner, without necessarily being printed, such as, for example, for cutting open webs, wrapping around the rolls, etc.
Due to the fact that only a limited amount of a web can be unwound from a roll, it is required for an uninterrupted production process that the web, which runs off from the so-called old roll is adhered to a new web of a so-called new roll. For this purpose, the prepared web start of the new roll, which is provided with an adhesive strip, is pressed against the web of the old roll, which runs off, so that the web of the new roll is adhered to the web, which runs off from the old roll. After the adhering process, the web of the old roll, which runs off, is severed, so that the printing material web is unwound exclusively from the new roll after the splicing process.
The adhering of the web of the new roll to the web of the old roll, which runs off, can either take place when the web stands still at least in the reel splicer region, or this takes place fully automatically when the web runs, wherein this is preferably possible at maximally possible production speed.
Due to the fact that a time difference is at hand between the adhering of the web to the new roll and the severing of the web in the case of correspondingly high web speeds, a tail is thus created as part of the web of the old roll, which is connected to the web of the new roll by means of the adhesive point. The tails usually have a length of approx. 10 to approx. 60 centimeters.
Due to the fact that these tails are connected with the adhesive point to the web of the new roll only at its leading end, viewed in the web running direction, said tail can hang down for example, provided that the tail is arranged on the underside of the web, or the tail can detach at least partially from the web, in particular with the trailing edge in response to corresponding wrapping around rollers, etc. It is thereby either possible that the web is damaged by the mechanical resistance when the tail strikes against a part of the printing press and can tear, or components of the printing press, which are arranged in the region of the web, are damaged.
There is a significant risk of a production interruption due to a web tear caused thereby or of damages to machine components, in particular when film-like printing materials, such as, for example, plastic films, metal films or other comparable materials with a relatively high mechanical tear strength are processed.
A solution is known from DE 44 41 447 C1, by means of which tails, which hang down freely in this way or which detach, can at least be reduced in their effective length in that not only an adhesive strip for forming the adhesive point is attached to the web as connection of the web of the old roll with the web of the new roll, but in that an additional adhesive is applied in the region downstream from the adhesive spot.
Due to the fact, however, that the length of the tail varies for different reasons in practice—this is a function, for example, of the web speed during the adhering process, the position of the reflex marks to the adhesive point, the reaction speed of the adhering and cutting device—the length of the tail can be limited maximally with the solution known from DE 44 41 447 C1, because the adhesive application may under no circumstances go beyond the region of the tail so as to avoid web winders, web tears, damages to or contaminations of parts of the printing press, etc. This is so, because if a corresponding, applied adhesive is not covered by the tail, it adheres to the component or to the part, such as, for example a guide roller, draw roller, pressure roller or on a printing cylinder and leads to significant impairments, such as windings, blockage, web tears as well as to contamination there due to adhesion together with the web.